1. Field of the Invention
This invention is related in general to the field of electric motors. In particular, the invention consists of a highly inductive electric motor driven by capacitor discharge.
2. Description of the Prior Art
In U.S. Pat. No. 3,890,548, Edwin V. Gray discloses a pulsed capacitor-discharge electric engine. Gray introduces the concept of charging capacitors and using the stored energy from the capacitors to drive an electric motor to develop considerable torque through the magnetic repulsion action of rotor and stator cores wound with coils. Capacitors are discharged synchronously through these cores utilizing a control mechanism to position discharge elements. Discharge overshoot or back e.m.f. from the collapsing magnetic field in the coils is used to charge external batteries for conservation of power.
Gray's rotary electric machine is believed to operate on the principle of conservation of energy. Once rotation occurs, electric current is needed only at the instant of a capacitor discharge in order to advance the rotor.
An important aspect of Gray's invention is that two banks of capacitors are utilized; one to energize the stator coil and one to energize the rotor coil. Additionally, all the electric charge discharged from the banks of capacitors must be collected and either dispersed as waste energy through resistors or collected and sent to the batteries. This requires that a large amount of current pass through the discharge circuit. During the process of collecting this discharge energy, a large amount of the energy is lost. Additionally, the banks of capacitors must be fully recharged before the next discharge cycle. One additional aspect of Gray's invention is that a special motor must be designed and built to take advantage of his concept. Accordingly, it would be advantageous to have a circuit, similar to that disclosed by Gray, with the capacity to reuse a significant portion of the charge without requiring that it be sent back to the battery. Additionally, it would be advantageous to have a capacitor motor-driver circuit that energizes only the stator coil, rather than both the stator and the rotor. It would also be advantageous to have a capacitor-discharge motor circuit that works with electric motor designs that are common in the industry.
J. Snell has previously disclosed a variation of the Gray capacitive discharge, as illustrated in FIG. 1. Four motor coils are represented by the inductive circuit elements T1, T2, T3, and T4. Four capacitors, C1–C4 (respectively) are utilized to drive the four motor coils. Four switches and numerous diodes are utilized to establish the timing necessary to ensure the motor continues to rotate.
Initially, a charge is placed on C1. Switches are aligned to allow C1 to discharge through T1 and place a portion of its original charge on C3. A counter electromotive force is passed to C2. Additional switches are closed, allowing C3 to discharge through T3. This secondary discharge, while smaller than the original discharge through T1, provides some additional torque. In this manner, the residual energy captured by C3 is used to provide power to the motor. However, no provision is made to bring the charge of capacitor C3 to the level initially obtained by C1. Therefore, the amount of torque which may be supplied to the motor is significantly less during the secondary discharge than that available during the primary discharge. As with the Gray motor, Snell's invention requires that a special motor be designed and built to take advantage of his circuit, i.e., a motor having at least four coils that are electrically separate from each other. It would be advantageous to design a motor driver circuit that can take advantage of electric motors common in the industry. Additionally, it would be desirable to have a capacitor discharge motor driver circuit that provides a consistent level of torque during each discharge cycle.